Emanuel nominated Building Commissioner Michael Merchant, an attorney and City Hall insider who has held his post since the start of the current administration in May 2011, to replace CEO Charles Woodyard.

Woodyard's departure, effective Nov. 1, was announced Tuesday at a CHA meeting. Woodyard wrote in his resignation letter that he was "pursuing other opportunities that I hope will benefit my family and my career."

But Emanuel was frustrated with the pace of the agency's $1.6 billion Plan for Transformation, which was behind schedule when Woodyard took over the agency in September 2011, a City Hall source said.

Merchant, a former public defender and Peace Corps worker who got his start at City Hall under former Mayor Richard M. Daley, took over a Building Department that in recent years had been roiled by scandals, including a federal bribery probe known as Operation Crooked Code that led to the convictions of more than 20 people.

In that job, Merchant has led an effort to streamline the building permit process, clean up vacant buildings and speed up compliance with high-rise fire safety codes.

"I have been impressed with his leadership at the Department of Buildings and I look forward to working with him as CEO of the Chicago Housing Authority," Emanuel said in a news release announcing Merchant's appointment. The CHA board, also appointed by Emanuel, must approve Merchant's appointment.